Los Angeles Angels pitcher Garrett Richards, left, leaves the field with a trainer after being relieved during the fifth inning of the team’s baseball game against the Oakland Athletics in Oakland, Calif., Wednesday, April 5, 2017. (AP Photo/Jeff Chiu)

OAKLAND >> A day after Garrett Richards gave the Angels a scare when he came out of a game with cramping in his biceps, he was scheduled for a precautionary MRI on Friday in Southern California.

Although such tests are sometimes ominous, the Angels are still hoping that Richards does not have any serious injury.

“Our medical staff is going to look into things,” Manager Mike Scioscia said Thursday morning. “They are confident this isn’t connected to his other situation last year. We’ll wait for guidance. (Friday) he’ll be evaluated and have some tests done to see what’s going on.”

Richards tore his ulnar collateral ligament last year, following a start in which he was initially diagnosed with dehydration. He had stem-cell therapy and appeared to bounce back to full strength this spring. He had not allowed a run when he came out of Wednesday night’s game in the fifth inning.

Richards’ next turn in the rotation would be Tuesday. Because the Angels are off Monday, they could skip him and push him back, perhaps all the way to next Saturday.

“We’re going to wait and see what the medical staff decides as far as where he is,” Scioscia said. “At least you want him to throw a power (bullpen) to make sure he’s good.”

Richards said after Wednesday’s game that he’s not concerned. Scioscia said he actually wanted to stay in the game.

Ready to go

Jesse Chavez will be making his first regular-season start in an Angels uniform on Friday, and he’ll do so amid the pageantry of the home opener. For Chavez, an Inland Empire native, he’s particularly excited for the assignment.

“I can’t wait,” he said. “It’ll be great.”

Chavez said he’s never started an opener or any other game with that type of pregame hoopla, but he figures if he simply starts his routine about five or 10 minutes later than usual, he’ll be fine.

Quick hits

Ben Revere, Cliff Pennington and Carlos Perez all got their first starts of the young season in Thursday afternoon’s game. Scioscia said he will try to get regular starts for his bench players, since some of them — specifically Revere — are used to playing every day. “We have guys who can play every day and need to play some,” Scioscia said. “We’re going to use them accordingly to keep some guys fresher in our lineup, and keep the guys on the bench fresh to where they can contribute.” …

J.C. Ramirez bailed out the bullpen by working through eight outs late in Wednesday’s game. “One of the important features of our bullpen is the multi-inning look,” Scioscia said before Thursday’s game. “The last three nights we got 17 outs from Ricky (Nolasco), 15 from (Matt) Shoemaker and 14 from Garrett. That could really decimate a ’pen if it wasn’t for what J.C. did yesterday.” Yusmeiro Petit performed a similar service on Thursday, with two perfect innings of relief. …

Blake Parker struck out both batters he faced on Thursday. Parker has five strikeouts in two innings so far this season, after striking out 24 in 12-1/3 innings in the spring. …

Mike Trout made an error when a ball scooted past him in the outfield on Thursday. Scioscia said the outfield grass was wet from the rain, and that probably contributed. A’s outfielders made two errors when they had trouble picking up balls after they hit the ground. …

The Angels’ first replay challenge of the season didn’t go their way, despite the fact that from the angles shown on television they seemed to be correct. Revere was called out on a force at second to end the sixth inning. Had the Angels won their challenge, they would have had the bases loaded and the potential tying run at the plate. … Luis Valbuena, who is out with a strained hamstring, has been running on an Ultra G treadmill and hitting in the cage, Scioscia said. He is expected to be able to run on the field next week. Valbuena is not expected to be back in the lineup until late April or early May.

Jeff Fletcher has covered the Angels since 2013. Before that, he spent 11 years covering the Giants and A's and working as a national baseball writer. Jeff is a Hall of Fame voter. In 2015, he was elected chairman of the Los Angeles chapter of the Baseball Writers Association of America.